Car coupler



CAR COUPLER 3 Sheets-Sheet 1 Filed March 31, 1958 Jan. 26, 1960 w. J. METZGER 2, 22, 32

\ .CAR COUPLER Filed March 31, 1958 3 Sheets-Sheet 2 k K) \x i & Q

Jan. 26, 1960 w. J. METZGER 2,922,532

CAR COUPLER Filed March 31, 1958 3 Sheets-Sheet 3 Unitd States Patent F CAR COUPLER William J. Metzger, East Cleveland, Ohio, assignor to National Malleable and Steel Castings Company, Cleveland, Ohio, a corporation of Ohio Application March 31, 1958, Serial No. 725,032

3 Claims. (Cl. 213151) This invention relates generally to railway knuckle-type car couplers, and more particularly to the contour of knuckle-receiving pockets thereof.

An important activity of the car building industry in the United States has been to provide standard couplers made of cast components requiring little machine finishing. That is to say, the components are separately cast with sufficient dimensional accuracy to permit assembly thereof as cleaned, trimmed castings requiring no machining, into couplers which are reliable for positive operation throughout a lengthy service period.

Typical of the knuckle-type couplers comprising unmachined castings are the A.A.R. (American Association of Railroads) approved E and F types used extensively in interchange service in the railroads of the United States. Generally speaking, these couplers are designed to maintain full operability and dependability regardless of the great variation in the wear of coupled couplers and the many other conditions attendant to use in interchange service. The design of these couplers is closely controlled to exacting physical and dimensional standards by the railroad industry and the coupler manufacturers.

Through long experience, the industries which manufacture and use the E and F types of couplers have evolved a set of tolerances within which a large number of standardized dimensions and contours of the couplers must conform. However, it has been obvious for some time that under very severe conditions of use a transverse deformation occasionally occurs in the head of a knuckletype coupler which is characterized by an increase in the distance between the spaced lateral walls of the knuckle receiving-pocket. Such deformation adds to the longitudinal and lateral slack in the two coupled couplers and results in an increased wear rate. As a serious safety hazard, such deformation may be accompanied by fracturing of the coupler head.

It has been discovered that present contours of the knuckle-type couplers, while keeping within the requirements of the American Association of Railroads, fail to reliably provide for the proper absorption of'bufling forces by the coupler head. Upon some of the couplers, the buffing forcesappear to be absorbed at spaced points on opposite sides of the longitudinal axis of the coupler head and produce an undesirable wedging action between the knuckle of one coupler and the head of an opposing coupler. This is contrary to normal operation of such couplers, since a bufiing force'is intended to be transmitted from the front face of the knuckleof one coupler to the forwardly-facing rearward'surface in the knucklereceiving pocket of the other coupler in the longitudinal direction of the couplers. Disposition of these opposing surfaces at substantially right-angles with the longitudinal axis of the couplers is consistent with the basic design of the couplers whereby strength is provided in essentially their longitudinal direction.

The present design of knuckle-type couplers in interchange service does not assure infallible occurrence of satisfactory face-to-face abutment of opposed couplers in bufling operations.

, ranges.

Patented Jan. 26, 1960 Accordingly, it is a primary object of this invention to provide standard knuckle couplers of modified design which are potentially capable of being coupled with the other couplers in interchange service without the possibility of producing or being subjected to substantial wedging forces in butt operation.

An object ancillary to the foregoing object is the provision of a coupler contour whereby bufling forces are transmitted through a coupling in essentially the longitudinal direction of the coupling but permitting vertical and horizontal angling within standards set by the American Association of Railroads.

Another object is to provide a coupler contour which will require no change in present standard knuckle construction as prescribed by the A.A.R. and will assure com- I plete knuckle closure during coupling operations.

An additional object of this invention is to provide a coupler contour which will increase the efliciency of the coupler during operation and prolong its service life.

Still another object is to provide improved E and F types of couplers which will warrant approval of the Association of American Railroads for standard interchange service in substitution of the present E and F types in current railroad use.

The invention, in its broader aspects, consists of a knuckle-type car coupler comprising a head having a knuckle-mounting portion, a guard arm, and a buff section, the latter having a vertical forwardly-facing surface and extending transversely of the longitudinal axis of the coupler to connect rearward ends of the knuckle mounting portion and the guard arm whereby a pocket is formed for receiving the knuckle of an opposing coupler. The coupler also comprises a knuckle which is pivotally supported by the knuckle-supporting portion to cause the nose of the knuckle to laterally overlap a portion of the pocket in coupled or locked position of the knuckle. In this posi-' tion, the knuckle provides a forwardly-facing face which is substantially complementary to the face of the buffsection of the head. The dimensions of the knuckle are variable within predetermined dimensional tolerance The knuckle-supporting portions and the guard arm are spaced transversely of the longitudinal axis of the coupler adjacent to where they join with the buff section stu'face to provide a transverse dimension of the pocket within a predetermined tolerance range. The spacing of the guard arm and the knuckle-supporting portion enable complete rearward displacement of the knuckle of another similar opposing coupler having maximum dimensions within the pocket named above when the transverse dimension thereof is a minimum in the tolerance range named above. In completing rearward displacement, the knuckle of the opposed coupler eifects substantially full engagement of its face withthe face surface of the butt section.

In the accompanying drawing with respect to which the invention is described:

Fig. 1 is a fragmentary top plan view showing the relationship between coupled couplers embodying thethe old contour again appearing partially in dot-dash line.

Fig. 4 is a fragmentary top plan view showing the relationship between coupled prior art couplers inbufi position.

Fig. 5 is a fragmentary top plan view "illustrating anundesirable relative disposition of engaged nosev portions of a pair of coupled couplers.

pledposition. Disposed intermediatelyof the-arm. 10

andthe side :13 is-a generally U-shaped pocket. 14 adapted to receive the pivotal knuckleli of-an opposing coupler. verse. but?v section-160i the head which is substantially atright angles to the longitudinal draft; axis X-X of the. coupler. The-buff section lfi provides a vertical forwardly-facing.: bufiing surface- 17, slightly laterally extended as at 16a and merging in a concave comer surface'wherefromthe pocketwwall extends forwardly and transverselyoutwardly as' the innerguardarm-surface 28. The knuckle 15 has anose 7 and a front-facing transverse portion '20 which defines the. front bufiing face 18. .Asillustrated in Fig. 1, the knuckle portion 20 on the opposed coupler abutszthe :transverse head section 16 with the resulting contact between the surface 17 and the face 18 of opposed couplers. In order to provide reasonable bearing stresses inbutf operation, the surface 17 and the face were substantially complementary. Hence, the buffing forces transmitted through the cou plers, areapplied to the head 9-of each coupler substantially in the direction indicated by the arrowsin Fig; 1, parallel .to the draft axis XX-of thecouplers. In order to obtain and maintain the above described relationship betweenthe knuckle 15 and theipocket 14 inbuff position, the diagonally extending inner-side-28 of theguard arm 10 has been relieved, i.e., ofiset laterally, as compared with the standard E coupler design approved by the Association ofAmerican Railroads, and merges with the surface increment 16a to provide adjacent their juncture a clearance 8 in a manner which wilLhereinafterbe described. In'buffop'eration, a clearance 21 exists between the knuckles 15 whicheliminates the. tendency of the knuckles to engage and bend or bind relative to each other. 'In the bud operation'of apair of coupled couplers constructed in accordance with this invention, the couplers'will align-with (a) their longitudinal-axes Y-.Y coinciding with-draft axis -X-X of the coupling as awhole, (b) the front-surface of thebulf section of one couplerin-substantially complementary relation-with the knuckle face of the other coupler (c) the nose of one coupler 'in approximate contactwith the knuckle-supporting portion of the other coupler, (d) and a clearance between the inner guard arm'surface of one coupler and thenheel of the knuckle ofthe other coupler.

'Byway of comparisom'the relationship in bu ftposi tion: between theparts'of coupled A;A.R. standard'type' F-couplers employing the'priorartcontouris illustrated in Fig. 4. Fig. 4 is illustrative of the misfit which occurs in the'zcoupling of a pairl'. of couplers having-knuckles of the maximum size and pockets of-the minimumsizepen' pocket '14,such as would operate to enable bufi ing forces.

to be asbsor-bed by the head 9 and transmittedzprimarily ina direction parallel to the longitudinal axis XX..

Instead, in the arrangement which occasional1y=occurs in the prior art system, as shown in Fig. 4, contact cuts between 'the'heel 19 of knuckle15 and the diagonal inneniside' 30- of the guard arm= at point "H,-'=ai1d* be- The pocket-14is partially bounded by a-transtwen the nose 7 and the side wall of the socket 14 at point I.

Thus, buffing forces are, in the prior art coupler of Fig. 4, absorbed by the head 9 at spaced points on opposite sides of the longitudinal axis XX. Furthermore, it is evident that the "bufiing forces, indicated in an approximate manner by arrows B B B and B in Fig. 4, absorbed by the 'head*9 of either coupler, are

multiadirectional rather than being parallel to *the-couplerdraft axis"XX *and; giverise to action tending do split the coupler heads. IIt willalsobe observed rthat little or no clearance exists between the knuckles 15,

'indicatingtheundesirable" binding of the knuckles in buff along the draft surfaces thereof. vIt will be understood that the undesired clearance 22 is subject to variations from its form as shown on account of the standard (-A.A.R allowablertolerances permitted in the feasting of the coupler'head" andrthe knuckle.

In Fig. 2, the novel contour isillustrated in 'cleta'il lin connection with a'standardtype -F coupler. "Transverse line A-A is known-as the-;pulling line and is located 3%; inches forwardly of thepocket surface 17. According -to the contour, as-s'hown in 'solid lines, ;.the surface of a transverse-portion r16rnerges'. with a curved surface 23, the latter in-turn -merging with the surface of an axially-aligned knuckle-supporting lug or wall portion 24. The contour of portion 24, as viewed in plan ter-- P minatesinthat of the concavely curved throat 251- of'the knuckle. The transverse pocketsurface' 17 andthe increment-al-surface. portion 16aadded by this invention and providedby transversehead portion l6'm'erge with the concavecurvedsurface 27 whichrin turn.merges with ing, a lateral-surfaceon theknuckle rearwardly of the curve 25 may protrude slightly laterallybeyond the sur-' face 24 from between the'upper and lower-pivot or knuckle supportingdugs and be engaged by the .nose of an opposing coupler.

The prior art contour, shown partially in dot-dash line, extends along-the following surfaces, namely: curve 26,.lcurved portion-25, axially aligned wall portion- 24,

curve 23, lateral surfacex17, curve 29 (in dot-dash); and

diagonally extending inner side 30 (in dot-dash) ofthe' guard arm. 10. :Asshownpthe prior art-contourterminates at the same point N onthe guard arid-10 as does' the novel contour. Hence, it may be notedthat the-novel contour and the prior artcontour differ primarily in the disposition of the 'lateralsurface of the pocket formed by the guard arm. As indicated in' Fig. 2, curves 27 (novel contour) and 29 (prior art contour) of the F type coupler are struck with the same radius but the curve 27 isstruck from a point which is located laterally a greater distance-from the longitudinal center line of the couplerhead .than'isthe point from which" the curve 29 is "struck.

An' increasein the lateral distance from the longitudinal centerline' of /8 inch to-strike-lthe curve 27' hasbeen found-suflicient- 'to--'accomplish the objects of this 'invention'. Accordingly, laterall-y "shifting the location bf'thestrike point away from its draft or longitudinahaxis Y-Y (commonwith axis-XX in Fig. 1), results in the transverse coupler' head p'ortion*16 being laterally; extended an-equal amount,-as at 161:, andthe'inner side andthe frontbllfiing faceon the knuckle of another.

coupler to occur as previously described'in all-possible coupler dimensions within'the standard tolerance ranges 5 now'inuse. v p "However, the-extent to-which' the lateral pocket'surassesses face 28 in a type F coupler can be relocated in a direction away from the axis Y-Y must be no greater than that which will assure positive lock operation when opposed couplers are brought into position for coupling. Excessive relief of the inner guard arm surface 28 shown in Fig. 2 may provide too much freedom of the knuckle of one coupler in the pocket of the other coupler in a direction lateral to the longitudinal axis. As a consequence, the knuckle noses may interfere to such an extent as to prevent the split-second cooperation of coupler parts needed for successful coupler action.

Referring again to Fig. 1 and observing internally of the head 9, one side 71 of the tail 70 of the knuckle 15 abuts the inner side wallsurface 73 of the head in buff position wherein the other side 74 of the knuckle tail has a clearance 75 of about Mr inch with the head of the lock 76 in its lower locking position. This is the position of the knuckle most favorable to'the descent of the lock to its locking position. In order for the lock to descend to its lower position with certainty, the clearance of the knuckle tail with that space occupied by the lock head must not be substantially diminished during the coupling operation.

Hence, it is necessary in a coupling operation that the longitudinal axes of both couplers come into substantially common alignment at the instant of coupler impact with the convex nose portion 26 mating substantially with the concave nose portion 25 of the opposed coupler. The knuckle of the unlocked coupler is thereby permitted to reach its full buff position wherein its tail engages the side wall of the head. However, if the pockets of the coupler are enlarged to the extent that the couplers seek to intercouple with their longitudinal axes separated, e.g., /2 inch, the knuckles may engage along the rear convex nose surfaces 26 thereof, as sho'wn in Fig. 5, (rather than by the convex surfaces 26 engaging the concave surface 25) to such an extent that the knuckle of the unlocked coupler cannot reach substantially its full buff position. The knuckle tail of the unlocked coupler is thereby unable to get into clearance with the path to be followed by the head of the lock as it attempts to descend into locking position.

To understand such a coupler failure, it is necessary to take into account the recoil and vibration of coupler parts that take place at the instant of coupler engagement in a coupling operation. Hence, the clearance 8 provided as shown in Fig. 1, between the guard arm of one coupler and the heel surface of the knuckle of the other coupler, must not be so great as to allow such lateral misalignment of the couplers as to bring about the condition shown in Fig. 5. In a coupling operation, the lock 76 of the unlocked coupler is raised and must have clearance with the knuckle tail 70 while descending to locking position. With the nose 7 in lateral interference as a result of excess axial misalignment of respective couplers, the clearance 75 may be reduced to less than the width needed for descent of the lock. In the standard F coupler, the clearance 8 should no't exceed about inch in order to assure suflicient width of the clearance 75.

To assure that such sidewise relative displacement of type F couplers does not occur to hinder operation of the lock in the unlocked coupler, it is recommended that the point for striking the Fla-inch radius of the surface 27 be located at no greater than 3% inches from the longitudinal axis Y-Y. As shown, the striking point of the surface 27 is necessarily 1% inches forward of the point of tangency of the surface 27 with the pocket or bufiing surface 17. This dimension is greater by about A inch than in the prior art type F coupler. To assure that the coupler po'cket will accommodate the maximum size knuckle permitted by the A.A.R. standards, this dimension should not be less than 3%; inches (see Fig. 2). That is to say, this dimension is the minimum value in any tolerance range adapted.

G .,A type B coupler is not correspondingly hindered in its locking operation because of the greater longitudinal clearances normally provided for the knuckle in the pocket of the opposing coupler. Assuming there was suflicient lateral clearance in the pocket of a locked E coupler, the longitudinal spacing between the pulling face of the knuckle and the bufling face at the rear of the pocket is sufficient to permit lateral passage of its knuckle past the knuckle of another coupler coupled without binding therewith. Hence, there is not such inter-,

ference of the knuckle no'ses that would substantially reduce the internal clearance needed in the unlocked coupler for lock operation.

In the present invent-ion, no change is contemplated in the prior art construction of the knuckles of standard type E or F couplers. On the knuckle 15, the curve 31 on the heel 19 is still struck with the same radius and from the same striking point laterally of the longitudinal center line heretofore used in the standard type F coupler, as shown in Fig. 2.

Fig. 3 illustrates a standard type E coupler (as approvedby the Association of American Railroads) having a head 40 incorporating, as shown in solid lines, the novel contour of this invention. Transverse line B-B is known as the pulling line and is located 3 inches forward of the pocket surface 60. A standard construction BB is inch forward of the pulling line. The contour comprises point M, a diagonally extending inner side surface 41, a curved surface 42, a bufling surface on the transverse portion 43, a small extension 43alrof the surface 60, a curved surface 44, an axially aligned surface on the wall portion 45, and curved surfaces 46 and 47 connected in series to provide acontinuous surface. The prior art contour, shown partially in dot-dash lines, differs from the novel contour only in the diagonally extending surface 50 and the curved surface 51, as is seen in Figure 3. As with the type F coupler, the curves 42 and 51 are struck with the same radius but the curver42 has its striking point located a greater lateral distance from the longitudinal center line than does the curve 51. In this case, increasing the lateral distance from thelongitudinal center line from 3 inches (in the prior-art structure) to 3 inches, i.e., by inch, in locating the strike point for the curve 42'wasfound sufiicientto obtain desirable abutting contact between the transverse buffing portion 43 of the coupler head and the transverse portion of the knuckle 61 on an opposed coupler.

However, in order to avoid unintentional slip-out or uncoupling of coupled E couplers, and allowing for wear and service deformation, such as knuckle stretch, shifting of the striking point for the curve 42 should not exceed 3% inches from the longitudinal axis of the E coupler. This latter dimension exceeds the standard prior art measurement for locating the striking point by inch, and the measurement for the new contour herein described by inch. The minimum allowable measurement for the E couplerconsistent with the purposes of this invention is that shown by Fig. 3, i.e., 3 inches.

As illustrated in Figs.v 2 and 3, it will be seen that there is no change in the opening existing between point N or M and the respective noses 7 or 62 of either the F or E type couplers since points N and M are also terminal ends of the pocket contours of the prior art E and F types, respectively. This feature serves to keep the pocket contour of this invention within the standards set by the Association of American Railroads regulating permissible horizontal and vertical angling between couplers. Also, in relieving the inner sides 30 and 50 to form the new inner sides 28 and 41, respectively, the latter are more steeply inclined rearwardly.

In either type of coupler illustrated, but taking the type F coupler as exemplary, considerable interference may occur between the knuckle of the unlocked or entering coupler and the knuckle nose and guard arm of the unlocked or receiving coupler, if the couplers approach each other I with 1a slight-to-moderate lateral misalignment. suchdnterferenceoccurs'particularly at an intermediate stage during-coupling'in which theknuckle of theunlocked coupler has' i but partially passed-:into the po'cket': of the locked coupler. 'The engagement atthis instant is such that the heelof the unlocked knuckle slidingly engages the inner guard arm surface under conditions of high pressure and abrasion. 'The unlocked knuckle-is s'ubjected'alswto atorque force which causes the pulling or rear side of its nose to slidingly engage the pulling or rear side of the knuckle nose of the lockedv coupler.

Themore longitudinally inclined inner guard armsurface provided by the present invention substantiallyireduces the pressure withwhich the: unlocked knuckle? initially "engages the guard arm andknuckle 'Ofithfi' opposing coupler of J the prior. art under thei'ofiset' conditions: described: immediatelv'above.

Hence, the coupling action of the couplers, improved as herein directed, iis wsrnoothervand accompanied :*by greater certainty of coupling and less wear of'thepocket and knucklesurfa'ces than in the standard zpriors'art couplers. In further comparison, the serious-attritinnzof coupler parts resulting from Wedgingwhichinevitably occurred .in some of'the previous: couplers 'constructed within the standard- A.A.R'. prescribed dimensional rtoler-' ances, rhas' beene avoided by assuringa'thattthe': knuckle face in one coupler will squarely-engagethe head biifling surface of an opposing coupler. 1

Y The terms and expressions which: have been employed are used-as terms of description and not of limitationand there is no intention of excludingsuch equivalents-Billie invention described sor of the portions thereof aslfall within the purview of the claims.

.Whatais "claimed is:

1.: 'In a knuckle'jtype car coupler comprising; a head having a knuckle-mountingzportion; a guarduarrmaandaa bufi section having. a-flat 'verticakforwardlv-facing surface extending .in adirection transverselynof the longitudinal axis of the coupler to :connect: the rearward ends of 1 said knuckle-mounting: portion and the, guard arm and forming thereby apocket'for receiving the knuckle of asimilar coupler; a knuckle pivotally supported'bysaid head oomprisinga tailwextending rearwardly of the pivotal ,a'xisxof the knuckle and a; nose disposed'iforwardly ofasaidzzaxis; a lockmovable alonga path hetweenran. upwardcouplerunlocking position and a lower 1 locking position beside the tailv of the knuckle; said tail, inthe'bufi position of the coupler, resting with oneside thereofagainst an inner side wall surface of the-head with a clearance between the other side of the tail and the path of'the' lock;thedimensions of said: nose and said pocket being-so relatedthat, in the 'buii position of said coupler and a similar coupler intercoupled therewith whereina knuckle ofthe similar coupler and identical with said knuckle has its face in substantially plane engagement twith s'aid-bufi section surface and its. nose 'in -engagement with said knuckle mounting portion; the horizontal dimension. of the pocket in. a vertical plane normal to .the longitudinal: axis in parallel adjacent "relation Withsaid section surfaceais greater, at a minimum value, thanthe horizontalcdimension: of the nose of said identical knuckle toform'a clearance between therear portion "of the guard arm and theheeli-of said identical knuckle and, at a .maximum value, limiting such clearance to a width preventing rotationofthetail; away :from said wallsurfacethrough said clearance-betweenthe t'ail' and the path of the lock into said path.

2. A coupler according to claim 1. and .typifiedz'by the Association of American Railroads standard type-F: couplerwherein: a the juncture ofithei guard arm and the buff section; provides a concave arcuatevsurface generatedby a 1% -inch radius-having its strikingpoint 1% inchestforwar'dly. of said'surface of the buflf'section'and. inzthe'range ofifrom 3%g-.to-3% linchest'as measured in a horizontal plane "includingithe' longitudinal axis of thecouplertfrom said axis- 3."A coupler according-to claim 1 and .typifiediby the Association of vAmericanRailroads standard-type E cou-' pler wherein:.:the juncture of the guard arm; and the b'uifas'ection provides a concave arcuatesurfacegenerated by a l A-inch radius having its'striking point 1% "inches forwardly of the point'of tangency of'said arcuatecsurface and-inthe range of 3%; to 3 /4'inches as measuredin a horizontal plane including the longitudinal axis of the coupler from said axis.

References Cited in the file of. this patent UNITED STATES PATENTS 698,970 '-K1"akau ..:Apr.' 29, 1902 

